Absorbable bone anchor

ABSTRACT

A bone anchor is provided that can toggle in two planes for secure anchorage within a bone cavity. The bone anchor includes an oblique suture channel configured such that a suture strand extending through the bone anchor can be tensioned to toggle the bone anchor inside the bone cavity. The suture strand can be located on the same side of the anchor body to maximize the area of the anchor surface which engages bone, resulting in increased engagement into bone and resistance to tensile forces.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] Not applicable.

FIELD OF THE INVENTION

[0003] The invention relates generally to medical devices andprocedures. More particularly, this invention relates to an absorbablebone anchor system for attaching soft tissue to hard bone, and tomethods for attaching soft tissue to hard bone.

BACKGROUND OF THE INVENTION

[0004] Soft tissues, such as ligaments, tendons and muscles, areattached to a large portion of the human skeleton. In particular, manyligaments and tendons are attached to the bones which form joints, suchas shoulder and knee joints. A variety of injuries and conditionsrequire attachment or reattachment of a soft tissue to bone. Forexample, when otherwise healthy tissue has been torn away from a bone,surgery is often required to reattach the tissue to the bone to allowhealing and a natural reattachment to occur.

[0005] A number of devices and methods have been developed to attachsoft tissue to bone. These include screws, staples, cement, sutureanchors, and sutures alone. Some of the more successful methods involveuse of a suture anchor to attach a suture to the bone, and tying thesuture in a manner that holds the tissue in close proximity to the bone.

[0006] The tissue may be attached to the bone during open surgery, orduring closed (e.g., arthroscopic) surgical procedures. Closed surgicalprocedures are preferred since they are less invasive and are lesslikely to cause patient trauma. In a closed surgical procedure, thesurgeon performs diagnostic and therapeutic procedures at the surgicalsite through small incisions, called portals, using instrumentsspecially designed for this purpose. One problem encountered in the lessinvasive, closed surgical procedures is that the surgeon hassignificantly less room to perform the required manipulations at thesurgical site. Thus, devices and methods are needed which will allow asurgeon to effectively and easily attach tissue to bone in the smallspaces provided by less invasive surgical procedures.

[0007] Proper attachment of soft tissue requires that it be placed inthe anatomically correct position to promote optimal healing.Conventional methods for attaching soft tissue to bone have typicallyused toggling anchors having sutures attached thereto. The suturesenable the soft tissue to be adjustably tied down in proximity to thebone surface after the anchor is inserted in a predrilled bone cavity.However, the suture strands extending from the bone anchor can oftenencumber the area in which the bone anchor is introduced, leading toless than ideal engagement of the anchor in the cavity. In a situationwhere the bone cavity needs to be larger than the bone anchor to provideclearance for both the suture strands and the anchor, it is difficult tothen effect sufficient engagement of the anchor to the bone.

[0008] There is thus a need for an improved system for anchoring softtissue to bone which provides optimal purchase into bone to preventloosening of the anchor in the bone cavity. Further, there is a need foran improved system for anchoring soft tissue to hard bone which enablessuture strands to be located on the same side of the anchor body inorder to maximize the area of the leading surface of the bone anchorwhich engages bone, resulting in increased engagement and resistance totensile forces. It would also be advantageous to provide a fullyabsorbable suture anchor and system.

SUMMARY OF THE INVENTION

[0009] The present invention avoids the aforementioned problemsassociated with conventional toggling anchors by providing a bone anchorthat can toggle in two planes for secure anchorage within a bone cavity.The bone anchor is configured such that the suture strands can belocated on the same side of the anchor body to maximize the area of theleading surface which engages bone, resulting in increased engagementand resistance to tensile forces.

[0010] In an exemplary embodiment of the present invention, a boneanchor is provided for anchoring tissue to bone having an elongate bodyextending between a first leading end and a second trailing end. Theelongate body defines a longitudinal axis of the anchor. Between thefirst and second ends are two opposed surfaces and a plurality ofsidewalls adjacent to and extending between the two opposed surfaces.Extending from one of the sidewalls is a flared portion configured toengage and anchor into bone. The elongate body also includes at leastone suture channel for passage of a suture strand therethrough. Thesuture channel is obliquely angled with respect to the longitudinal axissuch that applying tension to a suture strand extending through thesuture channel will force the bone anchor to toggle in two planes. Thistwo-way toggling action enables a better interference fit of the boneanchor in the bone cavity.

[0011] In one aspect of the present invention, the bone anchor mayinclude a notch for engaging a portion of the suture strand. The anchormay also include two suture channels. Preferably, the suture channelsare misaligned with respect to the longitudinal axis of the body. A finextending from one of the sidewalls can also be included.

[0012] In another aspect of the present invention, the bone anchor caninclude an elevated region that includes extra material near the firstleading end of the body. Bone anchor can also include a depressed regionnear the second trailing end wherein material is removed from thisdepressed region to provide clearance for the suture thread.

[0013] In a preferred embodiment, the bone anchor can be entirelybioabsorbable. However, the bone anchor may also be formed of anon-absorbable polymer or metal. A method is also provided by which adetached tissue may be securely attached to bone in an anatomicallycorrect position using the bone anchor of the present invention.

[0014] Further features of the invention, its nature and variousadvantages, will be more apparent from the accompanying drawings and thefollowing detailed description of the drawings and the preferredembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1A is a cross-sectional view of an embodiment of the boneanchor of the present invention;

[0016]FIG. 1B is another cross-sectional view through the side of thebone anchor of FIG. 1A at lines 1B-1B;

[0017]FIG. 1C is a perspective view of the bone anchor of FIG. 1A;

[0018]FIG. 2A is a side view of another embodiment of the bone anchor ofthe present invention;

[0019]FIG. 2B is a surface view of the bone anchor of FIG. 2A;

[0020]FIG. 2C is a perspective view of the bone anchor of FIG. 2A;

[0021]FIG. 3A is a side view of yet another embodiment of the boneanchor of the present invention;

[0022]FIG. 3B is a surface view of the bone anchor of FIG. 3A;

[0023]FIG. 3C is a perspective view of the bone anchor of FIG. 3A;

[0024]FIG. 4A is a cross-sectional view of another embodiment of thebone anchor of the present invention;

[0025]FIG. 4B is a cross-sectional view of another embodiment of thebone anchor of the present invention;

[0026]FIG. 5 depicts the bone anchor of FIG. 4B with two suture strands;

[0027]FIG. 6A is a surface view of yet another embodiment of the boneanchor of the present invention;

[0028]FIG. 6B is a side view of the bone anchor of FIG. 6A;

[0029]FIG. 6C is another surface view of the bone anchor of FIG. 6A;

[0030]FIG. 7A is a perspective view of the bone anchor of FIG. 6A with asuture strand;

[0031]FIG. 7B is a cross-sectional view of the bone anchor of FIG. 6A atlines 7B-7B-;

[0032]FIG. 8A is a surface view of yet another embodiment of the boneanchor of the present invention;

[0033]FIG. 8B is a side view of the bone anchor of FIG. 8A;

[0034]FIG. 8C is another surface view of the bone anchor of FIG. 8A;

[0035]FIG. 9A depicts a step in the method of deploying the bone anchorof the present invention;

[0036]FIG. 9B depicts another step in the method of deploying the boneanchor of the present invention;

[0037]FIG. 9C depicts yet another step in the method of deploying thebone anchor of the present invention; and

[0038]FIG. 9D depicts a final step in the method of deploying the boneanchor of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0039] Referring to FIG. 1A, an exemplary bone anchor 10 of the presentinvention is shown having an elongate body 12 extending between a firstleading end 14 and a second trailing end 16 for defining a longitudinalaxis L. First leading end 14 may be tapered as shown. The elongate body12 comprises two opposed surfaces 18 that extend between the ends 14,16, and a plurality of sidewalls 20 adjacent to and extending betweenthe two opposed surfaces 18, as shown in FIG. 1C. Near the secondtrailing end 16 and extending from one of the plurality of sidewalls 20is a flared portion 22. The flared portion 22 lends an asymmetricprofile to the bone anchor 10 and facilitates the toggling action of thebone anchor 10 once inserted inside a bone cavity. Flared portion 22 mayhave a sharp edge for penetrating into bone, though the edge does nothave to be a knife edge to effectively engage the walls of the bonecavity.

[0040] Although surfaces 18 are shown as flat, it is understood thatthey may be otherwise shaped or contoured. For example, they may becurved or rounded. Surfaces 18 may also include surface features such asroughened portions, or protrusions, that facilitate anchorage of thebone anchor 10 into the bone cavity. The sidewalls 20 that are adjacentto surfaces 18 may also be curved, rounded, or flat.

[0041] Elongate body 12 also includes a suture channel 24 for passage ofa suture strand through the bone anchor 10. As shown in FIG. 1B, suturechannel 24 comprises a through-hole 26 extending through each of theopposed surfaces 18 of bone anchor 10. Through-hole 26 extends into arecessed opening 28 at each of the surfaces 18, as best illustrated inFIG. 1C. Each of the recessed openings 28 is elliptically shaped, orovoid, as shown in FIG. 1A. Recessed opening 28 helps enable as much ofthe suture strand to lie flush with respect to surface 18 of the boneanchor 10 as possible, alleviating suture binding and pinching of thesuture strand between the anchor 10 and bone cavity. Recessed openings28 also reduce friction against the suture strand when tension isapplied. Suture channel 24 is obliquely angled with respect to thelongitudinal axis L of the body 12, as shown in FIGS. 1A and 1B. Thus,the recessed openings 28 of the suture channel 24 on opposed surfaces 18do not line up.

[0042] Because of the uniquely angled suture channel 24 of bone anchor10, a suture strand extending through this channel 24 can effect atoggling action in the bone anchor 10 in two planes when tension isapplied. This toggling action is enhanced by having the suture strandpass through the surfaces 18 of the anchor 10, rather than through thesides 20. In addition, the two-way toggling action resulting from theconfiguration of the suture channel 24 enables purchase of the entirelength of the flared portion 22 into bone, rather than just a corner ofthe anchor 10, or a small portion of the flared portion 22 as withconventional bone anchors with bone engagement edges. The increasedsurface area that can be anchored into bone results in increasedresistance of the anchor 10 to being pulled out with a tensile force.The increased surface area also enables the bone anchor 10 to achievepurchase in a wider range of bone hardness, since the engagement forceinto bone can now be distributed over a wider surface area, without thepotential of shearing off the flared portion 22 or cutting through thebone such as occurs with conventional bone anchors having small boneengagement edges. Ultimately, these features result in a bone anchor 10having an overall size which is smaller than conventional bone anchorswhile still being able to achieve optimal bone purchase. For instance,the anchor 10 of the present invention can have a diameter in the rangeof about 3.0 mm.

[0043] In addition to pulling on a suture strand 2 extending from theobliquely angled suture channel 24, bone anchor 10 can be toggled usingan inserter tool (not shown). As illustrated in FIG. 1A, extending fromthe second trailing end 16 into elongate body 12 is a bore 30 configuredto engage with a distal end of an inserter tool. Bore 30 can be threadedto threadably engage the inserter tool. When tension and deflection bythe inserter is applied to the bone anchor 10, after the anchor ispositioned within bone, the anchor 10 undergoes a toggling action, orrotation which results in the anchor 10 being oriented in a directionthat is not parallel with the longitudinal axis of the anchor-seatingbore 30. This toggling of the anchor 10 causes the anchor 10 to becomelodged within the bone. Thus, toggling of the bone anchor 10 can beachieved by tensioning the suture strand in the suture channel 24 and/ormechanically deflecting the bone anchor 10 with the inserter tool. Bothtechniques can work in synchrony to create an optimal interference fitof the anchor 10 within a bone cavity.

[0044] Bone anchor 10 of the present invention can be formed of abioabsorbable material. This provides the benefit of reducingimmunological problems associated with having a foreign substance withinthe body over a prolonged period of time. Bone anchor 10 can be composedof a suitable copolymer combination such as polylactic acid-polyglycolicacid (PLA-PGA), with a predominant fraction of PGA. Other bioabsorbablepolymers can be used to make the annular member according to the presentinvention. Examples of suitable biocompatible, bioabsorbable polymersinclude polymers selected from the group consisting of aliphaticpolyesters, poly(amino acids), copoly(ether-esters), polyalkylenesoxalates, polyamides, tyrosine derived polycarbonates,poly(iminocarbonates), polyorthoesters, polyoxaesters, polyamidoesters,polyoxaesters containing amine groups, poly(anhydrides),polyphosphazenes, biomolecules (i.e., biopolymers such as collagen,elastin, bioabsorbable starches, etc.) and blends thereof. For thepurpose of this invention aliphatic polyesters include, but are notlimited to, homopolymers and copolymers of lactide (which includeslactic acid, D-,L- and meso lactide), glycolide (including glycolicacid), ε-caprolactone, p-dioxanone (1,4-dioxan-2-one), trimethylenecarbonate (1,3-dioxan-2-one), alkyl derivatives of trimethylenecarbonate, γ-valerolactone, δ-butyrolactone, γ-butyrolactone,ε-decalactone, hydroxybutyrate, hydroxyvalerate, 1,4-dioxepan-2-one(including its dimer 1,5,8,12-tetraoxacyclotetradecane-7,14-dione),1,5-dioxepan-2-one, 6,6-dimethyl-1,4-dioxan-2-one 2,5-diketomorpholine,pivalolactone, α,α-diethylpropiolactone, ethylene carbonate, ethyleneoxalate, 3-methyl-1,4-dioxane-2,5-dione,3,3-diethyl-1,4-dioxan-2,5-dione, 6,8-dioxabicycloctane-7-one andpolymer blends thereof Poly(iminocarbonates), for the purpose of thisinvention, are understood to include those polymers as described byKemnitzer and Kohn, in the Handbook of Biodegradable Polymers, edited byDomb, et. al., Hardwood Academic Press, pp. 251-272 (1997).Copoly(ether-esters), for the purpose of this invention, are understoodto include those copolyester-ethers as described in the Journal ofBiomaterials Research, Vol. 22, pages 993-1009, 1988 by Cohn and Younes,and in Polymer Preprints (ACS Division of Polymer Chemistry), Vol.30(1), page 498, 1989 by Cohn (e.g. PEO/PLA). Polyalkylene oxalates, forthe purpose of this invention, include those described in U.S. Pat. Nos.4,208,511; 4,141,087; 4,130,639; 4,140,678; 4,105,034; and 4,205,399.Polyphosphazenes, co-, ter- and higher order mixed monomer basedpolymers made from L-lactide, D,L-lactide, lactic acid, glycolide,glycolic acid, para-dioxanone, trimethylene carbonate and E-caprolactonesuch as are described by Allcock in The Encyclopedia of Polymer Science,Vol. 13, pages 31-41, Wiley Intersciences, John Wiley & Sons, 1988 andby Vandorpe, et al in the Handbook of Biodegradable Polymers, edited byDomb, et al, Hardwood Academic Press, pp. 161-182 (1997). Polyanhydridesinclude those derived from diacids of the formHOOC—C₆H₄—O—(CH₂)_(m)—O—C₆H₄—COOH, where m is an integer in the range offrom 2 to 8, and copolymers thereof with aliphatic alpha-omega diacidsof up to 12 carbons. Polyoxaesters, polyoxaamides and polyoxaesterscontaining amines and/or amido groups are described in one or more ofthe following U.S. Pat. Nos. 5,464,929; 5,595,751; 5,597,579; 5,607,687;5,618,552; 5,620,698; 5,645,850; 5,648,088; 5,698,213; 5,700,583; and5,859,150. Polyorthoesters such as those described by Heller in Handbookof Biodegradable Polymers, edited by Domb, et al, Hardwood AcademicPress, pp. 99-118 (1997).

[0045] Exemplary bioabsorbable, biocompatible elastomers include but arenot limited to elastomeric copolymers of ε-caprolactone and glycolide(including polyglycolic acid) with a mole ratio of ε-caprolactone toglycolide of from about 35:65 to about 65:35, more preferably from 45:55to 35:65; elastomeric copolymers of ε-caprolactone and lactide(including L-lactide, D-lactide, blends thereof, and lactic acidpolymers and copolymers) where the mole ratio of ε-caprolactone tolactide is from about 35:65 to about 65:35 and more preferably from45:55 to 30:70 or from about 95:5 to about 85:15; elastomeric copolymersof p-dioxanone (1,4-dioxan-2-one) and lactide (including L-lactide,D-lactide, blends thereof, and lactic acid polymers and copolymers)where the mole ratio of p-dioxanone to lactide is from about 40:60 toabout 60:40; elastomeric copolymers of s-caprolactone and p-dioxanonewhere the mole ratio of ε-caprolactone to p-dioxanone is from about from30:70 to about 70:30; elastomeric copolymers of p-dioxanone andtrimethylene carbonate where the mole ratio of p-dioxanone totrimethylene carbonate is from about 30:70 to about 70:30; elastomericcopolymers of trimethylene carbonate and glycolide (includingpolyglycolic acid) where the mole ratio of trimethylene carbonate toglycolide is from about 30:70 to about 70:30; elastomeric copolymers oftrimethylene carbonate and lactide (including L-lactide, D-lactide,blends thereof, and lactic acid polymers and copolymers) where the moleratio of trimethylene carbonate to lactide is from about 30:70 to about70:30; and blends thereof. Examples of suitable bioabsorbable elastomersare described in U.S. Pat. Nos. 4,045,418; 4,057,537 and 5,468,253.

[0046] Preferably, the anchor 10 is formed from polylactic acid, or acomposite blend of tricalcium phosphate and polylactic acid. However, itis contemplated that bone anchor 10 of the present invention can also bemade of non-absorbable materials. For example, the bone anchor 10 may bemade of polysulfone, or a metal such as Titanium 6A1-4V.

[0047] Rather than having a closed nose at first leading end 14, thebone anchor 10 can have an open nose. As shown in FIGS. 2B and 2C, boneanchor 110 has the same features of anchor 10, with similar elementsbeing designated by the same number with the prefix “1”. Most notably,bone anchor 110 has a suture engaging notch 132 at its distal end 114.Suture engaging notch 132 allows the suture strand 2 passing throughsuture channel 124 to enter and exit on the same side of the boneanchor, as illustrated in FIGS. 2A and 2C.

[0048]FIGS. 3A-3C show yet another embodiment of the present inventionin which bone anchor 210 has two suture channels 224. The two suturechannels 224 enable the suture strand 2 to enter and exit the boneanchor 10 on the same side, as illustrated in FIGS. 3A and 3C. In allother respects, bone anchor 210 has the same features of anchor 10, withsimilar elements being designated by the same number with the prefix“2”.

[0049] In another aspect of the present invention, bone anchor 10′includes all the features of bone anchor 10, with similar elements beingdesignated with the same numbers followed by the suffix “′”, but canalso include a fin 34, as shown in FIG. 4A. Fin 34 extends from asidewall 20′ at approximately midway between the distal end 14′ andproximal end 16′ of the bone anchor 10′. Fin 34 acts as a shovel,providing an additional ledge for digging into bone and preventing theanchor 10′ from accidentally pulling out. In extra hard bone, the fin 34can serve as a compression fit element. Though fin 34 may not need to bea knife edge, fin 34 should have a sharp edge for penetrating into bonytissue.

[0050] Bone anchor 10′ also includes a bore 30′ that extends at an anglewith respect to the longitudinal axis L for engagement with an insertertool. The bore 30′ can have an angle in the range of about 15° from thelongitudinal axis L of the bone anchor 10′. Such an angled bore 30′ mayprovide additional leverage for toggling the bone anchor 10′ inside thebone cavity when the inserter tool is attached.

[0051] The additional features present in bone anchor 10′ may also beincluded in bone anchor 210′, shown in FIG. 4B. Bone anchor 210′ canalso have a fin 234 and a longitudinally offset, or angled bore 230′.Further, in bone anchor 210′ each of the suture channels 224′ ismisaligned with respect to the longitudinal axis L. That is, therecessed openings 228′ of the suture channels 224′ do not line up alongthe longitudinal axis, but are rather staggered with respect to thelongitudinal axis L. It is understood that bone anchor 210′ sharessimilar features with bone anchor 210, the same features beingdesignated with the same number followed by the suffix “′”.

[0052] It is contemplated that bone anchors 210, 210′ can be used withtwo suture strands 2. As depicted in FIG. 5, bone anchor 210′ can bethreaded with a suture strand 2 in each suture channel 224. By providingthe bone anchor 210′ with two suture strands, more precise andcontrolled toggling can be achieved as individual strands 2 aremanipulated at separate times and with differing amounts of tension.Since the suture channels 224′ are not aligned longitudinally, thisenables two suture strands 2 to be threaded through without substantialoverlap or encumbrance of suture strands 2 on the surface 218′ of thebone anchor 210′ where all the free ends of the strands 2 exit.

[0053]FIGS. 6A-6C, 7A, and 7B illustrate yet another embodiment of thebone anchor 310 of the present invention. Building on the features ofbone anchor 210′, bone anchor 310 includes fin 334 and two suturechannels 324. In addition, bone anchor 310 includes an elevated region338 surrounding leading end 314. Elevated region 338 includes both thesurfaces 318 and sides 320. The increased material in this elevatedregion 338 prevents over-rotation or flipping of the bone anchor 310 inthe bone cavity. Furthermore, the additional material helps clean bonedebris as the anchor 310 is inserted into the cavity.

[0054] As shown in FIG. 6A, the additional material forming elevatedregion 338 surrounding the two suture channels 324 creates a trough 334within the elevated region 338. Trough 336 connects an opening 328 ofone of the suture channels 324 with the other opening 328 of the secondsuture channel 324. The trough 336 enables a portion of a suture strand2 that passes from one opening 328 to another opening 328 to seatagainst the body 312 of the bone anchor 310. FIG. 7A shows a perspectiveview of bone anchor 310 having a suture strand 2 passing through thechannels 324. As illustrated in FIG. 7B, the combination of the twosuture channels 324 and trough 336 provide a smooth passageway for asuture strand to pass therethrough, without excess friction. Thesmoothness of the passageway and angled channel openings 328 enhancesthe slidability of the suture strand therethrough. In addition, thelarge radius of curvature of the suture passageway formed by the twosuture channels 324 and trough 336 facilitates ease of suture movement.

[0055] In yet another embodiment of the present invention, the boneanchor 410 can include not only an elevated region 436 but a depressedregion 438. As shown in FIGS. 8A and 8B, bone anchor 410 includes nearthe second trailing end 416 a depressed region 440 wherein material isremoved from one of the surfaces 418. An opening 428 of one of the twosuture channels 424 is located within this depressed region 440. Thedepressed region 440 provides clearance for the suture strand to lieagainst the body 412 of the bone anchor 410. Together with the trough434 on the opposite surface 418, shown in FIG. 8C, the depressed region438 helps maintain the slim profile of the bone anchor system of thepresent invention.

[0056] The anchors 10, 10′ 110, 210, 210′, 310, and 410 of the presentinvention may be used in the method described herein below for anchoringtissue to bone. For purposes of illustration, FIGS. 9A-9D depict themethod of using suture 410 in the context of an arthroscopic shoulderrepair, more specifically, attaching a detached labrum (as might resultfrom a Bankart lesion or rotator cuff tear) to the glenoid rim of ascapula. It will be understood, however, that the system and methoddescribed herein are equally applicable to connecting detached tissue inother contexts as well. Further, the method described is merelyexemplary of the steps involved in using any of the embodiments of theanchors of the present invention, and is equally suitable for anchors10, 10′, 110, 210, 210′, and 310.

[0057] Referring to FIG. 9A, a bore 502 is formed in bone 500 of thepatient. The diameter of the bore 502 should be about the same size asthe largest outer diameter of the bone anchor 410, e.g., about 3.0 mm.The length of the bore 502 should be of sufficient length to allow forcomplete seating of the suture anchor 410. As shown in FIG. 9B, aninserter tool 400 can be attached to bone anchor 410 for tapping theanchor 410 into the bore 502. Bone anchor 410 can be provided with anopen suture, i.e., a suture strand extending therethrough, or with asuture having a needle already attached for bringing soft tissue 510 inproximity to the bony structure 500 for reattachment. The suture needlecan have a first, tissue penetrating end and a second, trailing endattached to a loop of suture thread extending through bone anchor 410.

[0058] In FIG. 9C, the suture thread 2 extending from bone anchor 410has been threaded through the free end of detached labrum 510 using anyconventional method known in the surgical art. The bone anchor 410 canthen be tapped into bore 502, bringing the detached labrum 510 inproximity to shoulder bone 500. Because the top portion of the anchor410 is sized very close to the diameter of the bone cavity 502, thereresults an interference fit in this area when the anchor 410 is placedwithin the bore 502. This tight fit also allows the anchor 410 to pivotin place when a tensile force is placed on the suture strands. It iscontemplated that applying force on the inserter tool 400 can effecttoggling of the bone anchor 410 while inside the bore 502. In certainsituations, it may be desirable to perform this step to provideadditional securement of the bone anchor 410 prior to effectingadditional toggling by pulling on the suture thread 2.

[0059] Once the bone anchor 410 is properly inserted and the detachedlabrum 510 is in position, the inserter tool 400 can be removed. Thefree ends of suture thread 2 can be pulled to apply tension to thesuture 2 seated within the bone anchor 410. The anchor will toggle,e.g., about 90° with respect to the location of the suture strands 2.This toggling action can result in the flared portion 422 of the anchor410 being lodged into the side of the bone cavity 502. The body 412 ofthe anchor 410 is designed in such a way as to maximize the surface areaof this second trailing end 416. The bone anchor 410 is thus stabilizedin an interference fit within the bore 502, and the detached labrum 510is thereby attached to the shoulder bone 500 in the desired position, asillustrated in FIG. 9D. Free ends of suture thread 2 can then be securedtogether and the excess trimmed as is typical in these situations tocomplete the surgery.

[0060] It will be understood that the foregoing is only illustrative ofthe principles of the invention, and that various modifications can bemade by those skilled in the art without departing from the scope andspirit of the invention. All references cited herein are expresslyincorporated by reference in their entirety.

What is claimed is:
 1. A bone anchor for anchoring tissue to bone,comprising: an elongate body defined by a longitudinal axis, a firstleading end and a second trailing end, the elongate body comprising twoopposed surfaces between the first and second ends, and a plurality ofsidewalls extending between the two opposed surfaces, a flared portionformed on the second end and extending from one of the plurality ofsidewalls, the flared portion being adapted to engage and anchor intobone, and at least one suture channel formed in the elongate body forpassage of a suture strand therethrough, the suture channel extendingbetween the two opposed surfaces and being obliquely angled with respectto the longitudinal axis.
 2. The bone anchor of claim 1, wherein the atleast one suture channel further includes a recessed opening on eachsurface of the body.
 3. The bone anchor of claim 2, wherein the openingis elliptical.
 4. The bone anchor of claim 1, wherein the two opposedsurfaces are substantially flat.
 5. The bone anchor of claim 1, furtherincluding a notch at the first end of the bone anchor for engaging asuture strand.
 6. The bone anchor of claim 1, further including a finextending from one of the plurality of sidewalls in a direction oppositethe flared portion.
 7. The bone anchor of claim 6, wherein the fin islocated substantially midway between the first and second ends.
 8. Thebone anchor of claim 1, further including a threaded bore extending intothe elongate body from the second trailing end thereof.
 9. The boneanchor of claim 8, wherein the threaded bore extends at an angle withrespect to the longitudinal axis.
 10. The bone anchor of claim 1,wherein the anchor includes two suture channels.
 11. The bone anchor ofclaim 10, wherein the suture channels are misaligned with respect to thelongitudinal axis.
 12. The bone anchor of claim 11, wherein the firstand second suture channels are connected by a trough extending along oneof the surfaces of the elongate body, the trough being adapted to seat aportion of the suture strand.
 13. The bone anchor of claim 1, whereineach of the opposed surfaces has an elevated region at the first leadingend.
 14. The bone anchor of claim 13, further including a depressedregion at the second trailing end, the depressed region being located onone of the opposed surfaces.
 15. The bone anchor of claim 14, wherein arecessed opening of the first suture channel lies within the depressedregion.
 16. The bone anchor of claim 1, wherein the anchor isbioabsorbable.
 17. The bone anchor of claim 16, wherein the anchor isformed from the group consisting of polylactic acid, a composite blendof tricalcium phosphate and polylactic acid, and combinations thereof.18. A system for anchoring tissue to bone, comprising: a bone anchorcomprising an elongate body defined by a longitudinal axis, a firstleading end and a second trailing end, the elongate body including: twoopposed surfaces between the first and second ends, and a plurality ofsidewalls extending between the two opposed surfaces, a flared portionformed on the second end and extending from one of the plurality ofsidewalls, the flared portion being adapted to engage and anchor intobone, and at least one suture channel formed in the elongate body forpassage of a suture strand therethrough, the suture channel extendingbetween the two opposed surfaces and being obliquely angled with respectto the longitudinal axis; a loop of suture thread adapted to be attachedto the bone anchor; and a suture needle having a first, tissuepenetrating end and a second, trailing end, wherein the second, trailingend of the suture needle is attached to the loop of suture thread.
 19. Amethod for anchoring tissue to bone, comprising: forming a bone cavitywithin a bony structure; providing a bone anchor comprising an elongatebody defined by a longitudinal axis, a first leading end and a secondtrailing end, the elongate body including two opposed surfaces betweenthe first and second ends, and a plurality of sidewalls extendingbetween the two opposed surfaces, a flared portion formed on the secondend and extending from one of the plurality of sidewalls, and at leastone suture channel formed in the elongate body for passage of a suturestrand therethrough, the suture channel extending between the twoopposed surfaces and being obliquely angled with respect to thelongitudinal axis, the bone anchor further including a loop of suturethread attached to the bone anchor, and a suture needle having a first,tissue penetrating end and a second, trailing end, wherein the second,trailing end of the suture needle is attached to the loop of suturethread; threading the needle through a free end of the tissue; attachingan inserter tool to the bone anchor; inserting the bone anchor into thebone cavity; removing the inserter tool; applying tension on the suturethread to toggle the bone anchor and effect penetration into the bonecavity; and tying the suture thread to bring the free end of the tissueproximate to the bony structure.
 20. The method of claim 19, wherein thestep of inserting the bone anchor into the bone cavity includeseffecting toggling of the anchor with the inserter tool.